advertisement
The possible role of cerebrospinal fluid (CSF) pressure in glaucoma pathogenesis has long been postulated, with possible effects including direct deformation of the lamina cribrosa, impairment of axonal transport, and effects on retinal venous outflow.1 Berdahl et al.2,3 published the first clinical evidence indicating an association between glaucoma and low CSF pressure, but their work was retrospective with its associated limitations.
Ren et al. (50) investigated this issue with a prospective study of the CSF pressure and IOP in three groups: 1) glaucoma patients with normal IOP; 2) glaucoma patients with elevated IOP; and 3) normal controls. CSF opening pressure with lumbar puncture was measured in each group. For the normal controls, the lumbar puncture was performed at a previous time as part of an unrelated neurological assessment. The authors compared IOP, CSF pressure, and the trans-lamina cribrosa pressure (defined as the difference between IOP and CSF pressure) between the groups. They found that the CSF pressure was significantly higher in the control group than either glaucoma group. As well, the trans-lamina cribrosa pressure was significantly lower in the control group than either glaucoma group.
An association between CSF pressure and glaucoma has been demonstrated
This study clearly demonstrates an association between CSF pressure and glaucoma, confirming the results of Berdahl and colleagues. In particular, the trans-lamina cribrosa pressure appears to be strongly associated with glaucoma. Although the design of the study does not allow determination of causation, this study provides the most compelling evidence to date that CSF pressure may be involved in the pathogenesis of glaucoma. As well, the study was not designed to determine possible mechanisms by which an elevated trans-lamina cribrosa pressure may predispose to glaucoma. As the authors indicate, further work is needed to further elucidate the role of CSF pressure in glaucoma and possible mechanisms involved. Other questions that remain to be investigated include the measurement of CSF pressure during the nocturnal period when IOP is highest in most individuals in the physiologic positions.4